Name ____________________________________________________________ Date __________________
The Mole
Before You Read
Define the following terms.
atomic mass
the weighted average mass of the isotopes of an element
______________________________________________________________
atomic mass unit (amu)
one-twelfth the mass of a carbon-12 atom
______________________________________________________________
Chapter 2
Write the following in scientific notation
0.00582
5.82  103
________________________________
24,367
2.4367  104
________________________________
400
4  102
________________________________
Circle the significant figures in the numbers below.
75,600,000
0.00033
3.140
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Name ____________________________________________________________ Date __________________
The Mole
Section 1 Measuring Matter
Scan Section 1, using the checklist below to preview your text.
 Read all section titles.
 Read all boldfaced words.
 Read all tables and graphs.
 Look at all pictures and read the captions.
 Think about what you already know about this subject.
Write three questions that come to mind from your reading.
Accept all reasonable responses.
1. ____________________________________________________________
2. ____________________________________________________________
3. ____________________________________________________________
Use your text to define each term.
mole
the SI base unit used to measure the amount of a substance
_______________________________________________________________
Avogadro's number
the number 6.0221367  1023, which is the number of
_______________________________________________________________
representative particles in a mole
_______________________________________________________________
Counting
Particles
Use with pages 320–321.
List three common counting units and their values.
Accept all reasonable responses. Possible answers:
one dozen eggs  12 individual eggs
1. ____________________________________________________________
one pair of boots  2 individual boots
2. ____________________________________________________________
one ream of paper  500 sheets
3. ____________________________________________________________
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Name ____________________________________________________________ Date __________________
Section 1 Measuring Matter (continued)
Use with page 320–321.
Describe why chemists needed to invent a new counting unit.
The
number of atoms or particles in a given substance is so great
_______________________________________________________________
that it would be impossible to use conventional counting units.
_______________________________________________________________
List three forms of substances that can be measured using moles.
Accept all reasonable responses. Possible answers:
molecules
1. ____________________________________________________________
atoms
2. ____________________________________________________________
formula units
3. ____________________________________________________________
Converting
Between Moles
and Particles
Use with pages 322–323.
Analyze the usefulness of a conversion factor.
The conversion factor allows us to express a known quantity in
_______________________________________________________________
other units. We can switch unit systems because the units in a
_______________________________________________________________
conversion factor are equivalent to each other.
_______________________________________________________________
Write the equation for finding the number of representative particles in a
number of moles.
number of representative particles 
number of moles 
6.02  1023 representative particles
1 mole
Explain how you would find the number of moles that are represented by
a certain number of representative particles.
number of moles 
1 mole
number of

23
representative particles 6.02  10 representative particles
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Name ____________________________________________________________ Date __________________
Section 1 Measuring Matter (continued)
Particles-toMoles Conversion
Use with Example
Problem 1, page 324.
Summarize Fill in the blanks to help you take notes as you read Example
Problem 1.
Problem
Convert 4.50  1024 atoms of Zn to find the number of mol of Zn.
1. Analyze the Problem
Known:
4.50  1024 atoms of Zn
number of atoms  ______________________
6.02  10
1 mole Zn  ___________
atoms of Zn
23
? mol
Unknown: mole Zn  _______
2. Solve for the Unknown
the number of atoms  conversion factor  number of moles
1mole Zn
4.50  1024 atoms Zn 
___________
6.02  1023 atoms Zn
 number of moles
7.48 mol Zn
 __________
3. Evaluate the Answer
moles
three significant digits and is less than 10
The answer has _______
_________
REAL-WORLD CONNECTION
Suppose you were given each of the following tasks. Analyze which task(s) the mole would be an effective
unit for counting. Explain your answer.
A. Counting the atoms in a single grain of salt.
B. Counting the grains of salt in a very large mine.
C. Counting the grains of salt in the world.
The mole is an effective counting unit only for vast quantities occupying very small spaces.
_________________________________________________________________________________________
Therefore, only Task A can be performed most effectively using the mole as a counting unit.
_________________________________________________________________________________________
The
The grains of salt in a mine or in the world would result in a mole count too small to be of
_________________________________________________________________________________________
any use.
_________________________________________________________________________________________
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